The 17-year-old defensive midfielder joined the Ajax academy from Volendam six years ago, and has played through the various age groups. However, Ajax have now informed De Boer that he is no longer part of their plans.

With De Boer out of contract, Swansea City have swooped to bring the midfielder to the Premier League. De Boer has signed a three-year deal.

De Boer could have stayed in Netherlands with FC Twente or Utrecht but favoured the move to Wales.